Help.....Plants are drooping in bubble buckets!!!!

Hi guys,

Its my first DWC grow I am having problems with one of my girls, the leaves seem to be drooping on one of my plants the other seems ok but starting to show signs of it going the same way.

I AM RUNNING.........

2 big bang under a 400w hps ( currently 4.5 weeks in to veg 18/6 was planning on flipping at 5 weeks which is on sunday)

in hydraton pebbles in dwc buckets.

I am growing inside a closet 3.5ft wide x 2ft deep x 6ft high

ph is between 5.5 and 6.0

temps are at a fairly consistant 27 degrees,

not sure of humidity as i dont have a humidity meter

I am using Ionic grow at full strength since sunday along with quarter strength formulex

They have been as happy as larry so far, no problems growth was good, but over the last 2 weeks I have noticed the plant on the right in the picture has started to deteriorate somewhat and the leaves look as though its been over-watered and are drooping down and not holding there on weight.

The plants are so bushy i cant see the stem and the fan leaves seem to be an enormous size for the height of the plant.....should i be getting rid of a few fan leaves at this stage??

any help would be gratefully accepted.

^^^How close is your 400w hps to the canopy????

about 1.5 feet away??

I see a heat issue.